HPLC Determination of Robenidine in Feedstuffs

Abstract

An HPLC method of determination and fast monitoring of low concentrations of robenidine in feedstuffs was developed. Robenidine is extracted from sample with a dichloromethane - ethyl acetate mixture and, after purification of the extract on a Sep-Pak Silica column, is determined by ion-pair HPLC on C18 reverse phase with UV detection at 314 nm. The preseparation and separation of robenidine were optimized. The limit of determination, repeatability and recovery of the method are 400 μg kg^-1, 90 μg kg^-1 and 101.2 ± 6.5 %, respectively, at robenidine concentrations 0.4-4.5 mg kg^-1. In the interlaboratory comparison tests of the method at the 1 and 4 mg kg^-1 levels, the repeatability and reproducibility indexes were calculated, ranging from 18 to 20 % and from 32 to 44 %, respectively.